Note: Descriptions are shown in the official language in which they were submitted.
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1
SPARK PLUG
10
FIELD OF THE INVENTION
The invention relates generally to spark plugs for internal combustion
engines.
BACKGROUND OF THE INVENTION
Spark plugs for internal combustion engines have been known for more than 100
years. Although the design of spark plugs has improved considerably during
that time, there is
a continuing need for spark plugs which will further enhance engine
performance and,
hopefully, reduce the rate of fuel consumption.
The need for spark plugs which yield improved engine performance is especially
acute in the racing industry, where even small increases in engine performance
and/or small
decreases in engine fuel consumption can mean the difference between winning
and losing.
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SUMMARY OF THE INVENTION
The invention satisfies this need. The invention is a spark plug comprising
(a) a
central electrode having a proximal portion and a distal portion, the distal
portion having a
circular cross section with a longitudinal axis and terminating in a distal
end; and (b) a plurality
of peripheral electrodes, each peripheral electrode having a lower portion and
an upper portion
and being substantially identical in shape and dimensions, each upper portion
having a distal-
most point, each distal-most point being disposed in a central plane within
which the
longitudinal axis of the distal portion of the central electrode is wholly
disposed, the cross-
section of each upper portion taken along its central plane defining a convex
outer side and a
non-convex inner side, each convex outer side having a curved surface which is
tangent to a
plurality of tangent planes, all of which tangent planes intersect the
longitudinal axis of the
distal portion of the central electrode at points at or above the distal end
of the distal point of
the central electrode.
DRAWINGS
These and other features, aspects and advantages of the present invention will
become better understood with reference to the following description, appended
claims and
accompanying drawings where:
Figure 1 is a perspective view of a spark plug having features of the
invention;
Figure 2 is a plan view of one end of the spark plug illustrated in Figure 1;
Figure 3A is a cross-sectional view of the spark plug illustrated in Figure 2,
taken along line 3-3;
Figure 3B is an alternative cross-sectional view of the spark plug illustrated
in
Figure 2, take along line 3-3;
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Figure 4A is diagrammatic illustration of a first lower portion of a
peripheral
electrode useable in the invention;
Figure 4B is a diagrammatic illustration of a second lower portion of a
peripheral electrode useable in the invention;
Figure 4C is a diagrammatic illustration of a third lower portion of a
peripheral
electrode useable in the invention;
Figure 4D is a diagrammatic illustration of a fourth lower portion of a
peripheral
electrode useable in the invention;
Figure 4E is a diagrammatic illustration of a fifth lower portion of a
peripheral
electrode useable in the invention;
Figure 4F is a diagrammatic illustration of a sixth lower portion of a
peripheral
electrode useable in the invention;
Figure 4G is a diagrammatic illustration of a seventh lower portion of a
peripheral electrode useable in the invention;
Figure 4H is a diagrammatic illustration of an eighth lower portion of a
peripheral electrode useable in the invention;
Figure 41 is a side view of the lower portion of the peripheral electrode
illustrated in Figure 4H;
Figure 4J is a diagrammatic illustration of an ninth lower portion of a
peripheral
electrode useable in the invention;
Figure 4K is a side view of the lower portion of the peripheral electrode
illustrated in Figure 4J;
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Figure 4L is a diagrammatic illustration of a tenth lower portion of a
peripheral
electrode useable in the invention;
Figure 4M is a side view of the lower portion of the peripheral electrode
illustrated in Figure 4L;
Figure 4N is an alternative side view of the lower portion of the peripheral
electrode illustrated in Figure 4L.
DETAILED DESCRIPTION
The following discussion describes in detail one embodiment of the invention
and several variations of that embodiment. This discussion should not be
construed,
however, as limiting the invention to those particular embodiments.
Practitioners skilled in
the art will recognize numerous other embodiments as well.
As used herein, except where the context requires otherwise, the term
"comprise" and variations of the term, such as "comprising," "comprises" and
"comprised" are
not intended to exclude other additives, components, integers or steps. Thus,
throughout this
specification, unless the context requires otherwise, the words "comprise",
"comprising" and
the like, are to be construed in an inclusive sense as opposed to an exclusive
sense, that is to
say, in the sense of "including, but not limited to".
As depicted in the figures, all dimensions specified in this disclosure are by
way
of example only and are not intended to be limiting. Further, the proportions
shown in these
figures are not necessarily to scale. As will be understood by those with
skill in the art with
reference to this disclosure, the actual dimensions of any device or part of a
device disclosed in
this disclosure will be determined by its intended use.
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5 The invention is a spark plug 10 for an internal combustion
engine which is
capable of providing extraordinary performance. The spark plug 10 comprises a
central
electrode 12 and a plurality of peripheral electrodes 14. The invention is
illustrated in Figures
1-3.
The central electrode 12 has a proximal portion 16 and a distal portion 18.
The
distal portion 18 has a circular cross-section with a longitudinal axis 20.
The distal portion 18
terminates at a distal end 22. In one embodiment, the distal end 22 of the
central electrode 12 is
dome-shaped for a congruous blunt shape. For ease of manufacturing, the
central electrode 12
is cylindrical as with a typical spark plug.
In a preferred embodiment, the diameter of the distal portion 18 is between
about 0.125 inches and about 0.265 inches. This diameter of the distal portion
18 is about two
to three times larger than in a typical spark plug. The central electrode 12
is enlarged for
several reasons. One purpose is for spark stabilization. The enlarged
electrode stores up more
energy, thereby releasing a greater amount of electricity at the spark event.
A second purpose is
to cause continuous rapid ion movement during the ignition cycle that will not
break down,
even under extreme combustion pressure, as with racing engines.
The plurality of peripheral electrodes 14 are disposed equidistant from one
another around the central electrode 12 so as to define a circle having the
central electrode 12
disposed at its center. The peripheral electrodes 14 are typically integral
with a threaded base
cylinder 24. In the embodiment illustrated in the drawings, the plurality of
peripheral
electrodes 14 constitutes 8 peripheral electrodes 14. In all cases, it is
important that the number
of peripheral electrodes 14 is between about 3 and about 12. When the number
of peripheral
electrodes 14 is less than 3 or greater than 12, performance in an internal
combustion engine is
markedly reduced.
Each of the peripheral electrodes 14 is substantially identical in shape and
dimensions. Each peripheral electrode 14 has a lower portion 25 and an upper
portion 26. The
upper portion 26 has a distal-most point 28. As illustrated in Figures 1 and
2, the distal-most
point 28 of each of the peripheral electrodes 14 can be relatively sharp.
However, in other
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embodiments, the distal-most point 28 of each of the peripheral electrodes 14
may be more
rounded or flat.
As illustrated in Figure 2, each distal-most point 28 is disposed in a central
plane
30 within which the longitudinal axis 20 of the distal portion 18 of the
central electrode 12 is
wholly disposed. The cross-section of each upper portion 26 of each of the
peripheral
electrodes 14, taken along its central plane 30, defines a convex outer side
32 and a non-convex
inner side 34.
As illustrated in Figure 3A, each convex outer side 32 has a curved surface 36
which is tangent to a plurality of tangent planes 38, all of which tangent
planes 38 intersect the
longitudinal axis 20 of the distal portion 18 of the central electrode 12 at
points at or above the
distal end 22 of the distal point of the central electrode 12. In a typical
embodiment, the curved
surface 36 of the convex outer side 32 is smooth with preferably no
discontinuities.
Figure 3B illustrates an alternative cross-sectional view identical to that
which is
illustrated in Figure 3A, except that the inner side 34 defines a small flat
section 37 near the
distal-most point 28.
By the aforementioned design, the plurality of peripheral electrodes 14
resembles a fork that has been bent into a loop with the tines arcing inwards
to point at the
central electrode 12.
As also illustrated in Figure 3, the peripheral electrodes 14 are electrically
insulated from the central electrode 12 by a layer of bakelite 40 or other
suitable insulator.
As illustrated in Figures 4A-4M, the peripheral electrodes 14 can be provided
in
a variety of shapes. Figure 4A illustrates the cross-sectional shape of the
lower portion 25 of a
peripheral electrode 14 having a generally square cross-section. Figure 4B
illustrates the lower
portion 25 of a peripheral electrode 14 having a generally rectangular cross-
section. Figure 4C
illustrates the lower portion 25 of a peripheral electrode 14 having a
generally oval shape.
Figure 4D illustrates the lower portion 25 of a peripheral electrode 14 having
a generally
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circular shape. Figure 4E illustrates the lower portion 25 of a peripheral
electrode 14 having a
generally square shape but with rounded corners. Figure 4F illustrates the
lower portion 25 of a
peripheral electrode 14 having a generally rectangular cross-section, but with
rounded corners.
Figure 4G illustrates the lower portion 25 of a peripheral electrode 14 having
a generally
triangular cross-section.
Figures 4H and 41 illustrates the upper portion 26 of a peripheral electrode
14
having the shape of an eccentric cone. Similarly, Figures 4J and 4K illustrate
the upper portion
26 of a peripheral electrode 14 having a shape of an alternative eccentric
cone.
Figures 4L and 4M illustrate the upper portion 26 of a peripheral electrode 14
having a generally flat inner side 34 and an outer side 32 which in cross-
section taken along its
central plane 30, the inner side 34 has a generally flat surface and the outer
side 32 has a surface
having the shape of a circular arc.
Figure 4N illustrates the cross-section of an alternative upper portion 26 of
the
peripheral electrode 14 illustrated in Figure 4L wherein the inner side 34 is
somewhat concave.
Typically, the distal-most point 28 of each of the peripheral electrodes 14 is
spaced apart from the central electrode 12 by a distance of between about 0.04
inches and about
0.095 inches, most typically between about 0.05 inches and about 0.07 inches.
By the above-described unique design of the spark plug 10 of the invention,
the
spark plug 10 is capable of providing improved engine performance, including
the increasing of
horsepower and torque, by utilizing the excess energy from an ignition source
to cause rapid ion
movement that mixes with the incoming air/fuel in the combustion chamber. A
blast of
negative ions is mixed into the air fuel in the combustion chamber just prior
to ignition, during
the spark event and during combustion. This blast of ions changes the burn
characteristics of
the fuel by releasing more potential energy and slowing down the actual
combustion event.
This phenomenon is similar to raising the octane level of the fuel. During the
firing event ions
are cooling the tips. This event often results in rapid circular flow around
the central electrode.
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This phenomenon has the further advantage that the spark plug of the invention
need not be designed for one of a large number of specific heat ranges. For
most applications,
only one heat range is required. In contrast, with conventional spark plugs,
as many as 20
different designs are required, one for a different heat range.
By the design of the peripheral electrodes in the invention, negative ions are
separated out of the electrical charge flowing from the coil. The ions travel
along the periphery
of the negative electrodes, building momentum along the curves of the
peripheral electrodes
culminating at the distal portion and then blasting a pathway toward the
center electrode for the
spark plasma to travel. As the piston nears top dead center of the
compression/combustion
stroke the combustion chamber becomes highly pressurized. In this atmosphere
the spark
plasma is amplified and split so a plurality of sparks are emitted from the
variety of the ground
electrodes. As many as three distinct, highly energized spark kernels have
been observed
during high pressure testing.
The rapid ion movement impacts upon the central electrode and splays out into
the air/fuel charge, heavily ionizing said charge before, during and shortly
after the spark event.
Thus fully utilizing, completely, the electrical charge provided by the coil.
Another phenomenon that occurs in the use of the invention is that the moving
ions create a pressure shield beneath the central electrode and in the cavity
between the
insulator and the inner wall of the base shell. This pressure shield keeps
carbon from partially
burnt fuel and oil from contaminating the insulator and the inner wall of the
base shell, thus
avoiding potential shorting of the spark.
After ignition, the rapid ion movement cools down the flame front, thus
slowing
down the combustion event. This rapid ion movement process causes an increased
duration of
pressure on the descending piston top. This rapid ion movement combustion
process also
ensures a more complete burn, thus lowering the percentage of unburned
hydrocarbons.
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Another positive benefit concerning emissions is that the cooling aspect of
the
rapid ion movement keeps the NOx from rising. This is contrasted with
conventional spark
plugs wherein a higher heat range must be utilized to burn more hydrocarbons
(and such higher
heat necessarily produces more NO).
Finally, the design of the invention also produces a very strong and stable
spark
that can jump large spark gaps and under extreme combustion pressure, thereby
greatly
reducing misfires.
EXAMPLES
Dynometer charts are re-produced utilizing a high performance V-8 test engine.
These tests were conducted by an independent facility. No changes or
alterations were made to
the engine with the exception of the changing of spark plugs.
These charts demonstrate the increase in horsepower and torque achieved by the
sparkplug of the invention compared to a typical racing spark plug of the
prior art.
Example 1
In this example, the engine for testing was a 420 cubic inch Ford FE engine
with
an 850 cfm Holly carburetor and 38 degrees of timing. The stock spark plugs
were Autolite
3924 stock plugs set at a gap of .040 inches. The spark plugs of the invention
were Autolite
3924 stock plugs modified as illustrated in Figure 1, with a gap of .058
inches.
Stock Plug Invention Plug
RPM Trq Pwr Trq Pwr
3900 470.7 349.5 462.7 343.6
4000 505.1 384.7 503.5 383.4
4100 500.6 390.8 505.5 394.6
4200 499.8 399.7 507.6 405.9
4300 499.5 408.9 503.7 412.4
4400 498.2 417.4 501.8 420.4
4500 502.0 430.1 508.3 435.5
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5 RPM Trq Pwr Trq Pwr
4600 512.8 449.2 511.9 448.3
4700 516.2 461.9 523.0 468.0
4800 514.9 470.6 522.0 477.1
4900 519.0 484.2 521.7 486.7
10 5000 518.8 493.9 525.4 500.2
5100 520.9 505.8 522.4 507.3
5200 523.2 518.0 520.5 515.3
5300 519.4 524.1 524.3 529.1
5400 514.2 528.7 521.4 536.1
5500 514.3 538.6 518.6 543.1
5600 505.6 539.1 511.7 545.6
5700 500.0 542.6 501.6 544.4
5800 493.5 545.0 493.1 544.6
5900 483.5 543.1 487.0 547.1
6000 476.6 544.5 481.6 550.1
6100 471.4 547.5 469.4 545.2
6200 462.3 545.8 462.2 545.6
6300 452.7 543.0 458.0 549.4
6400 447.3 545.1 446.5 544.1
6500 437.6 541.6 435.8 539.3
Example 2
The engine for testing was an 812 cubic inch Ford engine with an 850 cfrn
Holly
carburetor and 38 degrees of timing. The stock spark plugs were Autolite 3924
stock plugs set
at a gap of 0.45 inches. The spark plugs of the invention were Autolite 3924
stock plugs
modified as illustrated in Figure 1, with a gap of .062 inches. In Example 2,
two tests were run
with the spark plugs of the invention.
Stock Invention 1 Invention 2
RPM Trq Pwr 'Dm Pwr r-Iq- Pwr
4000 495.9 377.6 496.6 378.2 506.0
385.4
4100 505.4 394.5 496.9 387.9 504.1
393.5
4200 503.5 402.6 501.1 400.7 505.0 403.8
4300 506.1 414.4 498.9 408.5 511.2
418.6
4400 511.9 428.9 508.8 426.2 510.0
427.2
4500 513.5 440.0 514.4 440.7 511.4
438.2
4600 512.3 448.7 515.4 451.5 517.6
453.3
4700 523.3 468.3 519.4 464.8 526.2 470.9
4800 530.2 484.6 531.2 485.4 527.9
482.4
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RPM 1... Pwr lifirg Pwr Trq Pwr
4900 528.6 493.2 529.7 494.2 527.1
491.8
5000 534.2 508.6 533.3 507.8 530.1
504.7
5100 530.9 515.5 531.4 516.1 532.9
517.5
5200 529.5 524.2 533.9 528.6 529.6
524.4
5300 524.1 528.9 528.1 532.9 526.9 531.7
5400 520.1 534.8 523.2 538.0 522.4
537.1
5500 519.2 543.7 523.2 547.9 517.8
542.2
5600 512.7 546.7 518.7 553.0 505.9
539.4
5700 498.7 541.3 511.1 554.7 503.7
546.7
5800 497.3 549.2 502.7 555.1 495.6 547.4
5900 494.1 555.0 493.6 554.4 492.8
553.6
6000 483.7 552.6 488.8 557.9 489.3
559.0
Having thus described the invention, it should be apparent that numerous
structural modifications and adaptations may be resorted to without departing
from the scope
and fair meaning of the instant invention as set forth hereinabove and as
described hereinbelow
by the claims.
